NTFS: Fix a potential overflow by casting (index + 1) to s64 before doing a

      left shift using PAGE_CACHE_SHIFT in fs/ntfs/file.c.  Thanks to Andrew
      Morton pointing this out to.

Signed-off-by: Anton Altaparmakov <aia21@cantab.net>

diff --git a/fs/ntfs/file.c b/fs/ntfs/file.c
index 7275338918132fe31eed51bddf2d48485d52c1b9..c73c8864cbad0748b02a490a7b70a0abd1c92324 100644 (file)
--- a/fs/ntfs/file.c
+++ b/fs/ntfs/file.c
@@ -248,7 +248,7 @@ do_non_resident_extend:
                 * enough to make ntfs_writepage() work.
                 */
                write_lock_irqsave(&ni->size_lock, flags);
-               ni->initialized_size = (index + 1) << PAGE_CACHE_SHIFT;
+               ni->initialized_size = (s64)(index + 1) << PAGE_CACHE_SHIFT;
                if (ni->initialized_size > new_init_size)
                        ni->initialized_size = new_init_size;
                write_unlock_irqrestore(&ni->size_lock, flags);